notes/docs/linenos-test.md

layout	title	nav_order
default	Markdown line number test	999

Configuration options

The default settings for HTML compression are incompatible with the HTML produced by Jekyll (4.1.1 or earlier) for line numbers from highlighted code -- both when using Kramdown code fences and when using Liquid highlight tags.

To avoid non-conforming HTML and unsatisfactory layout, HTML compression can be turned off by using the following configuration option:

{% highlight yaml %} compress_html: ignore: envs: all {% endhighlight %}

When using Kramdown code fences, line numbers are turned on globally by the following configuration option:

{% highlight yaml %} kramdown: syntax_highlighter_opts: block: line_numbers: false {% endhighlight %}

Line numbers can then be suppressed locally using Liquid tags (without the linenos option) instead of fences:

{% highlight yaml %} {% raw %}{% highlight some_language %} Some code {% endhighlight %}{% endraw %} {% endhighlight %}

Workarounds

To use HTML compression together with line numbers, all highlighted code needs to be wrapped using one of the following workarounds. (The variable name some_var can be changed to avoid clashes; it can also be replaced by code -- but note that code=code cannot be removed).

Code fences

{% highlight default %} {% raw %}{% capture some_var %}

Some code

{% endcapture %} {% assign some_var = some_var | markdownify %} {% include fix_linenos.html code=some_var %}{% endraw %} {% endhighlight %}

Liquid highlighting

{% highlight default %} {% raw %}{% capture some_var %} {% highlight some_language linenos %} Some code {% endhighlight %} {% endcapture %} {% include fix_linenos.html code=some_var %}{% endraw %} {% endhighlight %}

Credit: The original version of the above workaround was suggested by Dmitry Hrabrov at https://github.com/penibelst/jekyll-compress-html/issues/71#issuecomment-188144901.

Examples

Some unknown code in fences

// Javascript code with syntax highlighting in fences
var fun = function lang(l) {
  dateformat.i18n = require('./lang/' + l)
  return true;
}

# Ruby code with syntax highlighting in fences
GitHubPages::Dependencies.gems.each do |gem, version|
  s.add_dependency(gem, "= #{version}")
end

{% highlight ruby %}

Ruby code with syntax highlighting using Liquid

GitHubPages::Dependencies.gems.each do |gem, version| s.add_dependency(gem, "= #{version}") end {% endhighlight %}

{% capture code %} {% highlight ruby linenos %}

Ruby code with syntax highlighting and fixed line numbers using Liquid

GitHubPages::Dependencies.gems.each do |gem, version| s.add_dependency(gem, "= #{version}") end {% endhighlight %} {% endcapture %} {% include fix_linenos.html code=code %} {% assign code = nil %}

With the default configuration options, the following example illustrates the incorrect formatting arising from the incompatibility of HTML compression and the non-conforming HTML produced by Jekyll for line numbers:

{% highlight ruby linenos %}

Ruby code with syntax highlighting and unfixed line numbers using Liquid

GitHubPages::Dependencies.gems.each do |gem, version| s.add_dependency(gem, "= #{version}") end {% endhighlight %}